[skwasjer]

You do not need to filter the vertex/uv/normal list yourself, just drop it in the first section of the file like you already have, and then you can break up the file in subobjects with an g-token... Then you can use the same vertex/uv/normal list, still all in one big file. This is equaly valid as putting shorter lists of vertex/uv/normals before each face list (although the latter would be a little better to read visually).

v x,y,z
..
..

vn x,y,z
..
..

vt u,v(,w)
..
..

g object1
(usemtl)
f vi/vti/vni etc...
..
..

g object2
(usemtl)
f vi/vti/vni etc...
..
..